1. Technical Field
The present invention relates to apparatuses that determine the presence or absence of branching and merging of roads.
2. Description of the Related Art
Japanese Patent Application Publication No. JP2009035213A (to be referred to as Patent Document 1 hereinafter) discloses a lane departure prevention apparatus that prevents departure of a vehicle from its traveling lane. Specifically, the apparatus sets, based on navigation information, a traveling section where the probability of the vehicle changing its traveling lane is high. Further, the apparatus determines a direction in which the tendency for the vehicle to depart from its traveling lane in the set traveling section is high. When the probability of the vehicle changing its traveling lane in the determined direction is high, the apparatus suppresses a lane departure prevention control from being performed. In contrast, when the probability of the vehicle changing its traveling lane in the determined direction is low, the apparatus allows the lane departure prevention control to be normally performed so as to prevent the vehicle from departing from its traveling lane in the determined direction.
Japanese Patent Application Publication No. JP2010221859A (to be referred to as Patent Document 2 hereinafter) discloses a vehicle driving support system that identifies the traveling lane of a vehicle in real time and controls driving of the vehicle based on the identified traveling lane. Specifically, the system includes a camera, a white line type recognition unit, a white line type storage unit, a white line type estimation unit and a controller. The camera captures images of a road on which the vehicle travels. The white line type recognition unit recognizes, based on the images captured by the camera, the type of a white line which defines the traveling lane of the vehicle. The white line type storage unit stores therein the white line type recognized by the white line type recognition unit. The white line type estimation unit estimates, when the current white line type cannot be recognized by the white line type recognition unit, the current white line type based on the past white line type stored in the white line type storage unit. The controller controls driving of the vehicle based on the current white line type recognized by the white line type recognition unit or estimated by the white line type estimation unit.
However, it is impossible for both the lane departure prevention apparatus disclosed in Patent Document 1 and the vehicle driving support system disclosed in Patent Document 2 to accurately determine the presence or absence of branching and merging of roads.